Electric riveting



F. L- DYER.

ELECTRIC RIJETING.

APPLICATION HLEO AUEIB 19:5.

1,305,078. Patented May 27, 1919 u/vEl/MA r/r- HAMMER 0 24. VA K. 4

UNITED STATES PATENT OFFICE.

FRANK L. DYER, OF HONTCLAIB, NEW JERSEY.

anaemic luvn'rmo.

To all whom it may concern:

Be it known that I, FRANK L. Dunn, a citizen of the United State",residing at Montclair in the county of Essex and'the State of hew Jerseand having a post-oflice address at iberty street, New York city, haveinvented certain new and useful Improvements in Electric Riveting, ofwhich the following is a full, clear, and exact sp'ecif cation.

My invention relates to various new and useful improvements in electricriveting, the method being particularly adapted for use for riveting inconnection with shipbuilding, and my object is to provide for suchimprovements in the art as will permit a riveting operation to beperformed more quickly than by present methods and which will result ina more uniform and regular product.

In riveting operations as now carried out in shipbuilding or analogousfields, it is the practice to heat the rivets to the desired temperaturein a small blacksmiths forge, to then pass them successively to theholder-on, who inserts each of them in the desired rivet hole, and theriveter thereupon by means of a pneumatic tool heads over or upsets ,theend of the rivet. If the rivet blank in this way is heated to too-high atemperature the metal melts and the blank has to be discarded.Furthermore, during the time that the blank is exposed to the air afterheating its temperature drops so that often the riveting be comes adiflicult' operation and frequently bad jobs are made, necessitating thetedious burning out of the rivet by an city-acetylene flame and thesubstitution of a good rivet.

Electric riveting is desirable because it 'iermits the rivet, blank tobe brought to the iesired high temperature, whereupon the rivetingoperation can be immediately performed before the blank has a chance tocool and in factthe heating current can be maintained during theriveting operation. But

efl'eotive electric riveting as heretofore pro posed can be carr'i'edout only in connection with relatively small plates and relatively smallrivets sincethe plates must be small enough to be received within thethroat of the riveting machine, the heating current passing imctly fromoneelectrode to the other through the rivet blank and a single powerSpecification of Letter: Patent.

Application filed August 18. 1918. Serial Io. 250.117.

Patented May 27, 1919.

ful pressure being applied to upset the rivet bv causing the electrodesto approach each other and the rivets must be small enough to emit themto be headed in this way n shipbuilding the plates are very large and itwould be impracticable to apply a riveting machine with a throat bigenough to straddle the plates and frames of a ship under constructionsince such a device will be too heavy and unwieldy to be effectivelyoperated in competition with the present methods.

With my improved method instead of applying direct pressure to theheated blank as heretofore proposed with electric riveting, I upset thehead of the rivet by a succession of blows from a pneumatic tool withoutin any way interfering with the passage of the heating current throughthe rivet blank which may thus be kept at the maximum tempera ture foreffective riveting during the head ing operation.

Furthermore; with my im roved method, I so arrange the riveting too orgun that in addition to heading the rivet, it also acts as an electrodeto apply the heating current to the rivet, whereby the operator by oneand the same tool effects the heating of the rivet. and by a succeedingoperation effects the usual riveting operation. In this waytimc is notlost between the heating and riveting operations and in fact, ifdesired, the heat ing 0 rrent may be kept on during the rivetingoperation. With my improved me 0d, moreover. preferably the gun and theho. ing on tool are equipped with clue trodes by which the current willbe difl'useil through the plates, thus permitting, as I will explain,the conductors to be carried on one side pf the plates. In this Way, bythe very act engaging these tools with the rivet, the electrodes willautomatically close the circuit through the plates in the neighborhmulof the rivet, whereby a minimum resistance will be included in theexterior heating circuit and that resistance at all times will be.coustant, thus permitting more certain anduniform. work. Furthermore,this arrangement permits the riveter and holder on to move .the onlything needed being that the transformer shall be movable convenientlyfrom place to place.

In order that the invention may bt' better understood attention .isdirected to the accompanying drawing forming a part of thisspecification and in whichfi Figure 1 1s a diagrammatic cross sectionalview showing two ship plates riveted togather, illustrating the carryingout of my method by means of a simple form of apparatus.

Fig. 2. a cross sectional view on the line 22.of Fig. 1.

Fig. '8. an enlarged sectional view showing one of the rivets in placeand illustrating rticularly the insulating of the rivets m the plates,and I Fig. 4. a oorres nding view of a modification in which t e rivetis split longitudinally so as to provide a continuous passage .for thecurrent through the two legs of the tion except that before being usedthey may be coated with a suitable insulatin material 5, by which thehead andshank of the rivet will be insulated from the metal plates orparts. The voltage of-the heating current being ver low the insulatingthus secured need not e especially efi'ective. If desired, instead ofapplying insulating .material to the. blanks, an extremely thininsulating sheath of insulation like mica or asbestos may be applied tothe shank of the rivet blank and to the under side of the head thereofso as to insulate the same. This insulation also reduces heat conductionfrom the blank and facilitates raising the temperature thereof to thedesired point.

6; represents the tool used by the holderon who presses said toolagainst the rivet blank toihold the same in position while it is beingheated and headed. This tool is made preferably of copper at its innerend and for its main 'part is composed preferably of some material whichis a poor conductor of heat, such as wood. If desired the copper end maybe water cooled as is conimon with electric heating operations.

Extending radially outward from the tool 6 near its end are copper arms7, carrying shoes 8, which come in contact with plate or frame. Asuitable number of these copper arms are preferably used giving as muchof a cross section as possible to the heating cursaid pluu or beingacted upon in t e usual way by t e piston of said tool to impose uponthe rivet a series of rapidly recurring blow when the throttle of saidtool is opened.

Surroundin the block 9, is a copper ring 12, insulated mm the block byinsulation 13, and said ring carries a number of copper arms 14,corresponding to the arms 7, each provided with a shoe 15, makingconnection with the lateor frame 2.

A num r of these arms 14, are used to prevent undue heating' in thesecondary circuit exterior to the rivet blank.

The secondary 16, of the transformer is connected to the ring 12, andplunger 9, so that the heating current will be concentrated in the rivetblank 4, to heat the same, while this current will be difiused in thebalance of the secondary circuit which is of relatively low resistance.

The primary 17, of the transformer is supplied with current of thedesired voltage,

and in the primary circuit is a switch 18; which the operator may openor close preferably by means of hisfoot so as to cut the heating currentofl or on as may be desired.

In operation, heatin current of the desired voltage is appli to heat upthe rivet blank as quickly as possible while the blank is being pressedby the two workmen between the tools 6 and 11, and when the blank hasreached the proper temperature the riveter may then cut oil the currentor he may reduce the current, or he may keep the full strength of thecurrent maintained in the blank. He then operates the throttle of thepneumatic tool, which strikes a succession of rapid blows on the heatedblank and thus forms the head of the rivet. this operation beingperformed very rapidly because the rivet blank can be maintained at ahigher temperature than is now possible and the "metal will thus be moreplastic and more easil worked.

ith the modification shown in Fig. 4 I provide the rivet blank'withinsulation 5, and also with the lon itudinal slot 19, extend ng in theshank a ost through to the head thereof. With this modification all thatthe holder-on has to do is to the head of the rivet so as to'ho d it inplace. Instead of a single block 9, I make use of two water cooledblocks 20 and 21, engaging the two legs of the blank so that the heatingcurrent will traverse said legs and bring the blank to the desiredtemperature, whereupon the same operation is per ress OD formed forheading the blank as I have a]- ready described.

It will be understood, in carr ing out my improved method, that the insuating of the rivet blanks from the plates or frames throu h which theypass need not be eflectn fact, provision may be made to cause the rivetblank to engage the surrounding metal with a good contact, either byfitting the blank accurately in the hole or by filling in around theblank with a conducting material. When this is done, the heating currentwill be concentrated at the end of the blank, instead of along itsentire shank, since where the blank makes contact with the metal of theplates or frames, the current has an opportunit to diffuse and therewill be less heating e ect. But the end of the blank will be brought tothe desired temperature, which manifestly is all that is necessary sincethe upsettin of the metal is limited to the end where t e head is to beformed. When the method is carried out in this way, it is obvious thatthere will be diffusion of current between the blank and the surroundingmetal in proportion to the degree or extent of such contact. If thecontact is poor, there may be very little diffusion and most of thecurrent will traverse the blank and be concentrated therein, but whenthe contact is good and suliiciently extensive there may be relativelylittle heating of the blank except for its exposed por tion and for ashort distance within the rivet hole. In the latter case, i. e., wherediliusion between the blank and surrounding metal can be counted on, orwhere such difiusion is especially provided for, there will be no needof special conductors to carry the current from the holding-on tool tothe plate, since the current passes directly to the plates from therivet blank.

Furthermore, it will be understood that instead of makin connection forthe secondary circuit to the plate by means of con ductors carried withthe riveting tool as I have described, there may be a direct connectionmade with the plate by temporarily bolting a contact plate to the same,said contact plate being shifted from lace to place as the rivetingprogresses. n other words, instead of making a connection between one ofthe secondary leads to the ring 12, arms 14, and shoes 15 to the plate2, a contact plate may be tem orarily bolted to the late 2 and the seconary lead connected irectly to that plate. his connection may be reliedupon for any number of riveting operations, so long as the place ofriveting is not so far removed as to interpose undesirable resistance.

I prefer however to use separate electrodes carried by the tool 11 and(when the heating current is to traverse the entire length of the rivet)by the tool 6, because in this way the exterior heating circuit isalways the same and includes a minimum of iron or steel, namely, onlythe thickness of the two plates. If a separate contact plate is used, asabove proposed, and as suggested, for example, in patent to Thomson, No.555,131, dated February 25, 1896 (see data C the exterior heatingcircuit, will he of varying resistance according to the distance betweenthe contact plate and the rivet being worked on. Therefore, the amountof heat lost in the exterior heating circuit will be a variable factor,and the riveting operation is less likely to be uniform than when theresistance of the exterior heatipg circuit is constant, as will be thecase where the electrodes are carried by the tool or tools.

By exterior heating circuit I mean the secondary circuit of thetransformer, except the short portion at the rivet where a usefulheating effect is secured.

Having now described my invention, what I claim as new therein anddesire to secure by Letters Patent is:

1. The method of electric riveting which consists in applying anelectrode to the unheaded end of the rivet blank, passing the heatingcurrent therefrom through the rivet blank to heat the same and inapplying after heating a succession of rapidly recurring blows to saidelectrode to form the head on the rivet blank, substantially assetforth.

2. Themethod of electric riveting, which consists in applying anelectrode to the unheaded end of the rivet blank, applying a secondelectrode to the other end of the blank, passing the current betweensaid electrodes to heat the blank, and in completing the circuit betweensaid electrodes through the plates which are being riveted,substantially as set forth.

4 3. The method of electric riveting, which consists in applying anelectrode to the unheadcd cud oi the rivet blank, applying a secondelectrode to the other end of the blank, passing the current betweensaid elec trodes to heat the blank and in com leting the circuit betweensaid electrodes trough the plates which are being riveted by electrodeswhich diffuse the current, substantially as set forth.

' 4. The method of electric riveting, which consists in applying anelectrode to the unhcaded end of the rivet blank, applying a secondelectrode to the other end of the blank, passing the curient betweensaid electrodes to heat the blank, in com leting the circuit betweensaid electrodes tl irough the plates which are being riveted and inapplying a succession of rapidly recurring blows to the first electrodeto form the head on the rivet blank, substantially as set forth.

5. The method of electric riveting, which consists in a plying apneumatic tool or gun to the rivet blank, passing a heating current fromthe said tool to the rivet blank to heat the same, and in operating saidtool to apzply a series of rapidly recurring blows to t forth.

6. The method of electric riveting, which consists in applying apneumatic tool or gun to the rivet blank, passing a heatinfi currentfrom the said tool to the rivet blan 10 tn heat the same, closing thecircuit through e heated blank, substantially as set,

the plates being riveted, and operating said tool to apply a series ofrapidly recurring blows to the heated blank, substantially as set forth.

This specification signed and witnessed 15 this fifteenth day of August,1918.

FRANK L. DYER. Witnesses: ABRAHAM F As'rovE, Com B; WRIGHT.

